When a loudspeaker works reproduces a sound via a voice coil built therein, the voice coil becomes a source of heat in the loudspeaker. The voice coil heats up as the electric current flows through. Part of the heat generated by the voice coil is transferred to the air and other members of the loudspeaker around the voice coil. Materials of which the members of the loudspeaker are made exhibit a poor thermal conductivity, e.g. the magnetic members of the loudspeaker. As the heat transfers to these members, the heat is not effectively liberated but it is rather stored in these members over time.
The heat stored in these members of the loudspeaker increases the temperature of the loudspeaker. The high temperature handled by the loudspeaker during sound reproduction may cause critical issues, such as high power compression, demagnetization of the magnet members, and moreover it can damage some of the members of the loudspeaker leading to a severe loudspeaker failure.
A solution for this problem is to equip extra pieces made of material having good thermal conductivity, such as aluminum, to the loudspeaker in strategic places, and with specific shapes, so that the efficiency of heat dissipation in the loudspeaker increases. These pieces are so called heat sinks.
Heat sinks help dissipate heat, however, in some circumstances this is not enough and the heat released by the heat sinks into the adjacent air needs also to be moved, so that the temperature in the loudspeaker can be further reduced.
Apart from choosing materials which can handle high temperature, another conventional solution that can help the loudspeaker to achieve a good power handing is to pierce the structure of the loudspeaker at specific areas so that the hot air can be released from cavities of the loudspeaker. However, the expelled hot air stays in the surroundings of the loudspeaker. The hot air that was removed may come back into the loudspeaker again without a proper control of the airflows.